Two Xbox Live Profiles?

[tremberz]

Is it possible for two Xbox Live profiles to be in the same game on the same xbox and both of them getting achievements? I know you can do co-op on the same xbox however I was having trouble on a mission on HARD difficulty and my cousin may be coming round and he has an xbox live profile so I was wondering if i used his gamerprofile as well as mine would we both get achievements? any help would be appreciated.

[AK Punk]

For the co-op story my sister and I played local (both profiles on the same HD) and we both got achievements while we played. Mine was XBL hers was only a profile though. Make a silver account and try it out but I'm sure that two XBL profiles will still get achievements. Hope that makes sense to you. If not go ahead and ask more questions.

[LOCKDOWN123]

You don't even have to sign in with the second profile to get the achievement...for the primary profile